How to calculate a 30% profit margin on cost?
If “30% on cost” means profit equals 30% of cost, profit = 0.30 × cost and selling price = cost × 1.30. Example: $100 cost → $30 profit → $130 price.
Detailed answer
Clarify definitions: here margin *on cost* (markup on cost) means profit = 30% × cost. Basic Percentage finds the profit dollars; Value After Change with +30% on cost gives the selling price. Retail “margin % of selling price” is different—profit ÷ price—so always confirm which base your contract uses.
Relationship context
Accounting margin-on-sales vs markup-on-cost are both percents but with different denominators; mixing them changes break-even points.
Worked example
Example cost = 100. Profit: Basic 30% of 100. Price: Value After +30%.
Same math as the live tool: Basic Percentage, Percentage Change, Percentage Of, and Value After Change.
Percentage Calculator modes
One page covers four patterns: percent of a total, part-to-whole percent, percent change between two values, and final value after a percent increase or decrease—with recent history on your device.